Dioxo-bis-guanamines and resins therefrom



Unitcd States Patent DIOXO-BIS-GUANAMINES AND RESINS THEREFROM FredericC. Schaefer, Darien, and Leo A. Landers, Stamford, Conn., assignors toAmerican Cyanamid Company, New York, N.Y., a corporation of Mame NoDrawing. Application December 28, 1955 Serial No. 555,799

11 Claims. (Cl. 26067.6)

This invention relates to bis-guanamines, to polymers therefrom and tomethods for preparing them. More particularly, it relates to substituteddioxo-bis-guanamines represented by the formula:

where R R R and R are the same or different hydrogen or lower alkylradicals and R is a (lower) alkylene, or a (lower) alkylidene, or a(lower) alkyli dene diphenyl radical, such as for example, methylene,ethylene, propylene, butylene, pentylene, ethylidene, propylidene,butylidene and isopropylidene diphenyl.

It is an object of the present invention to prepare a new and novelclass of the aforementioned substituted dioxo-bis-guanamine compounds.It is a further object to present new and novel storage-stable resinsprepared therefrom.

In the past, bis-guanamines which lack a substituted diether linkagehave been reacted with formaldehyde to form resins. Such resinsunfortunately tend to harden or cure upon standing. Frequently, it isdesired to prepare a storage-stable resin syrup which does not hardenupon standing and yet cures rapidly when needed. This objective has beensuccessfully attained in the use of the novel class ofdioxo-bis-guanamines mentioned above. Unexpectedly, a storage-stableresin syrup which can be rapidly cured, is prepared from the latterclass of compounds upon reaction with a formaldehyde solution.

In general, the dioxo-bis-guanamines of the present invention may beprepared by reacting dicyandiamide with an appropriate dinitrile in thepresence of an inert organic solvent. Some illustrative dinitriles are:

a,a-Ethylidenedioxy bisacetonitrile Bis-l-cyanoethyl acetalBis-l-cyanoethyl formal 1,4-bis(cyanomethoxy)butane 1,3-bis(cyanomethoxy) -2,2-dimethylpropane 2,5-bis(cyanomethoxy)pentanel,4-bis( l-cyanoethoxy) butane 2,2-bis(4-cyanomethoxyphenyl)propaneBis-cyanomethyl acetal Bis-cyanomethyl formal The above listedillustrative dinitriles may be readily prepared by methods known to theart. For example, the a,a-alkylidenedioxy dinitriles can be prepared bycondensing an appropriate aldehyde or acetal with an a-cyanohydrin asdisclosed in US. Letters Patent 2,398,757.

In accordance with the process of the present invention, a dinitrile ofthe type illustrated above. reacts with a' slight molar excess ofdicyandiamide, preferably in the presence of an alcoholic potassium,sodium, or lithium hydroxide solution. The reaction is furtheradvantageously conducted in the presence of an inert organic solvent,such as a glycol ether as for example ethylene glycol monomethyl ether,or alcohols such as propanol or butanol. Novel bis-guanamines are thusproduced which contain two bridging ether groups in the side chain ofthe bisguanamine molecule.

The reaction is carried out at temperatures ranging from 20 C. to about200 C. It has been found that temperatures below about C. arecommercially unsuitable because the rate of reaction is quite slow.However, the rate of reaction increases as the temperature is increased.While the rate of reaction is rapid above 150 C., the yield of desiredbis-guanamine is substantially decreased due to side reactions. A goodpractice therefore is to conduct the reaction at temperatures between 75C. and 150 C.

In order to facilitate a further understanding of the invention, thefollowing examples are given primarily for purposes of illustratingcertain more specific details thereof. The scope of the invention is notto be deemed limited thereby except as defined in the claims. Unlessotherwise stated, the parts given are by weight.

EXAMPLE 1 Preparation of a,a'-ethylidenedioxybisacetoguanamine N H2N-CCCHg-0-OH-O--OH2C O-NH; a i H. N

40 parts of a,a'-ethylidenedioxybisacetonitrile, '52 parts ofdicyandiamide, 3 parts of potassium hydroxide and 120 parts of butanolare successively added to a reaction flask and heated at about C. forone hour. The reaction flask is then cooled to approximately 22 C. Next,the crystalline solids content in the flask is recovered by filtrationand the filtrate is discarded. The solids content is washed withmethanol and then with water. The product is dried at about 100 C. A 77%yield, based upon theoretical a,a-ethylidenedioxybisacetoguanamine whosedecomposition point is 260 C., is obtained. The product can berecrystallized from Water. So-recrystallized product melted at 272 C.274C. analyzing as follows:

Calcd for C H N O z 38.9%, C; 5.4%, H; 45.4%, N. Found: 39.1%, C; 5.5%,H; 45.1%, N.

EXAMPLE 2 Preparation of a,a'-ethylidenedioxybispropioguanamine N H: NH:

A mixture of 93.5 parts bis-l-cyanoethyl acetal, 102.4 partsdicyandiamide, 5 parts of potassium hydroxide pellets and 240 parts ofbutanol is heated to 80 C. in a reaction vessel. At that temperature, amildly exothermic reaction begins. slowly to about C. Where it ismaintained by gentle cooling. After the exothermic reaction hassubsided, the reaction mixture is diluted with an additional parts ofbutanol and is heated under reflux for one hour. The reaction vessel iscooled to room temperature. The solids content in the flask is filteredand washed with methanol followed by a water wash. After drying at 110C., the

This causes the temperature to risea e-1. 54. I. t

crude product is recovered in a 92% yield and has amelting-pointof"272"-'C.-274 C. (dect); Recrystallization from 50%aqueous Z-methoxyethanol results in increasing theethylidenedioxypropioguanamines melting point to -2=78=' C.279- C; (docEXAMPLE 3 .Pliepflratianiof 'a,af methylenedioxybispropioguanamine NIraq-f w-on ofonr-o-on-f TNH:

Amixture of 3.5-parts of bis-,l-cyanoethyl formal, 5.0parts-ofldicyandiarnide, 0.5 part of potassium hydroxide,

and 7.par ,ts.of.ethylene glycol monomethyl ether is heated EXAMPLE 4Preparation of a,a'-tetramethylenedi0xybisacetoguanamine N N mN-fToHg--0CHgOHzCHzCHr-OCH:( TNH, N N N N N32,: NHz

Into a reaction-flask is added 284. parts 1,4-(bis cyanomethoxy)butaneto a stirred mixture of 298 parts dicyandiamide, 14 parts potassiumhydroxide and 96 parts butanol; However, the dinitrile [1,4-(biscyanomethoxy) butane] is added over :a minute interval to the mixturewhile maintainingthe temperature at 115 C. The mixture is refluxed foran additional hour. The reaction vessel is then: cooled to roomtemperature. The crystalline solids content is recovered by filtration.Water Washing removes the slightly developed color in the soliddioxo-bis-guanamine. The latter is next dried at about 100 C. A 94%yield is obtained. The melting point of the dioxo-bis-guanamine is 270C.275 C.

EXAMPLE 5 The procedure of Example 3 is repeated except that thedinitrile is l',3'-bis("cyanomethoxy)=2;2' dimethylpropane. The latterdimethylpropane is characterized by a boiling point of 146 C.148 C. at 5mm. Hg pressure and its index of refraction, 11 is 1.4354. Thebisguanamine so-obtained is recovered in good yield (80.5 and has amelting point of 230 C.232? C.

EXAMPLE 6 Preparation of 1,3-dimethyl-1,S-trimethylenedioxybis:.(acetoguanamine) N CH CH, N

i 0 (3 NH; NHQ In themanner ofthe process setforth inEXampIe-Z, 2,5 biscyanomethoxy.) pentane is reacted with dic'yan-- diamide to give 85%.yieldsof 1,3-dimethyl-1,3-trimethyla enedioxybisacetoguanamine, whosemeltmgpoint is 250" C.252 C. and analyzing as follows:

Percent Percent O H Calc'd f0! CmHnNmO: 44. 56 6. 33 Fo 44. 29 6. 51

EXAMPLE 7 Preparation ofa,a'-tetramethylenedioxybis(propioguanamine)Repeating the procedure. of-Example 4, the reactionof.1,4-bis(1:cyanoethoxy)butane vwith dicyandiamide under the conditionsdescribedvthereinn A 94% yieldof bis guanamine having a meltingpoint of2,70? C.-275. C. is; obtained.

EXAMPLE 8.

Preparation of 4,4-isopropylidenebis(aephenoxy- F/ N H Preparation ofa,a'-neopentylenedioxybisacetoguanamine i 1 NHL acetoguanamine) I. NHL

The procedure of; Example- 3 is; repeated except-rthat2,2-bis(4-cyanornethoxyphenyl)propane; reacts with dl-r cyandiamide togive a good yield of 4,4-isopropylidenebis a-phenoxyacetoguanamine) Aspreviously stated, the bis-guanamines *of the present invention are goodresin formers: Whenthe bis-guarv amines are reacted with aqueousformaldehyde; they form"- storage-stable syrupysolutions or, if desired;thesyrupy solution is de-watered to formadr'ied'resin. In either event,a fast curing but storage-stable material" isob tained. The followingexamples will illustratethe-pre ferred embodiments of this aspect.

EXAMPLE 9 One mol of a,a-ethylidenedioxybisguanamine prepared... by theprocess of Example 2 is reacted with four mols of formaldehyde inaqueoussolution. containing 50% solids at a pH of 6.0-7.0 at C. Heating is con:tinued until the clear solution begins to cloud, indicating: that thehydrophobic endpoint has been reached.v Heating is then discontinuedjUpon cooling the syrupy pro d-.. uct is sol,uble ;in 50%1alcohol-watermixture. The..sol ution is stable even after 12 weeks of storage andcures up rapidly under acid conditions at pH between 5 and 6.9. A curedfilm has good color, clarity, and resistance to alcohol and causticsolution. The syrupy resin is further useful as a laminating resin. Whenthe syrupy resin solution is evaporated and the resultant solidpulverized, a non-hygroscopic powder, useful as a laminating resin, isprepared.

EXAMPLE One mol of a,or-neopentylenedioxybisacetoguanamine, prepared bythe process of Example 5, is reacted at 100 C. with about four mols offormaldehyde in aqueous solution containing 50% solids at a pH ofbetween 6 and 7. The mixture is heated until the hydrophobic end pointis reached. Heating is then terminated and the hydrophobic product isfound to be soluble in 50% alcoholwater mixture. After 12 weeks, thesyrup was found to be storage-stable curing rapidly at a pH of from 5-7.

In four separate runs, the products of Examples 1, 3, 4 and 10 weresubstituted for the product of Example 5 in the procedure set forth inExample 10 above. The syrupy resins formed in each run are foundstorage-stable and cure rapidly.

We claim:

1. A dioxo-bis-guanamine of the formula:

i ll 4 N 11TH: NH;

in which R R R and R are selected from the group consisting of hydrogenand methyl and R is selected from the group consisting of a loweralkylene, a lower alkylidene and a lower alkylidene diphenyl radical.

2. The monomeric compound a,a-ethylidenedioxybisacetoguanamine of theformula:

I NE: N

3. The monomeric compound e,u'-ethy1idenedioxypropioguanamine of theformula:

4. The monomeric compound u,ot'-methylenedioxybispropioguanamine of theformula:

NE: NH;

5. The monomeric compound a,a-tetramethylenedioxybisacetoguanamine ofthe formula:

NE: NH:

6. The monomeric compound a,u'-neopentylenedioxybisacetoguanaminerepresented by the formula:

7. A process for preparing the monomeric bis-guanamine of claim 1 whichcomprises: reacting at a temperature of from about 20 C. to about 200 C.one mole of a dinitrile of the general formula:

wherein R R R and R are selected from the group consistingof hydrogenand methyl radicals and R is a radical selected from the groupconsisting of lower alkylene, lower alkylidene and diphenyl substitutedlower alkylidene with two moles of dicyandiamide.

8. A storage-stable resin syrup prepared by reacting a monomericbis-guanamine of claim 1 with formaldehyde in a mol ratio of about 1:4in aqueous solution at C. and at a pH of from 5-7.

9. A storage-stable resin syrup characterized by its fast curingproperties prepared by reacting at about 100 C. one mol ofa,a'-ethylidenedioxybisacetoguanamine with four mols of formaldehyde inaqueous solution containing 50% solids at a pH between about 6 and 7.

10. A storage-stable resin syrup characterized by its fast curingproperties prepared by reacting at about 100 C. one mol ofa,or-neopentylenedioxybisacetoguanamine with four mols of formaldehydein aqueous solution containing 50% solids at a pH of between 6 and 7.

11. A new and useful polymer prepared by reacting a monomericbis-guanamine defined in claim 1 with formaldehyde in a mol ratio ofabout 1:4 in aqueous solution at 100 C. and at a pH of between about 5and 7; and dewatering resultant syrupy material to obtain a drystoragestable resin product capable of curing up rapidly.

References Cited in the file of this patent UNITED STATES PATENTS2,398,757 Loder et al Apr. 16, 1946 2,401,607 Bruson -1 June 4, 19462,510,761 Simons June 6, 1950 2,653,143 De Benneville et al Sept. 22,1953

1. A DIOXO-BIS-GUANAMINE OF THE FORMULA: